What F91 Means
Miele’s G-series problem summary describes F91 as load size registration being inactive. The machine can no longer work out how much it has been given to wash, so the automatic load-sensing that adjusts water and energy use is switched out.
Common Causes of F91
- Sensor providing the load-size input has failed
- Wiring to that sensor broken or unplugged
- Related problem elsewhere causing the control to disable the function
🔧 One Safe Check You Can Try
Nothing needs to be done urgently. Use a named program rather than the fully automatic one, and load to a normal level rather than half-filling, so the fixed cycle you choose is a reasonable match for what is inside.
⚠ Why You Shouldn't Go Further Than That
- Load registration depends on other inputs the machine is already taking, so this code is often a sign of something else and is best read alongside the rest of the problem memory.
- Reading the full problem memory needs service mode, which is how a technician sees whether F91 stands alone or sits behind a bigger problem.
- The sensing involved is in the water path in the base of the machine, not behind an accessible panel.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.
Technical Reference
- Code
- F91
- Appliance
- Miele dishwasher
- Maker documentation
- Miele owner manuals and use & care guides
- Checked
- September 2026
Code meanings can change between control generations. Before acting on a code, match the full model number on your appliance's rating label against the manual for that model. We are an independent repair service, not affiliated with Miele & Cie. KG.